Muffler



Aug. 11, 1931. HAAS 1,817,981

MUFFLER.

Filed Sept. 13. 1929 in after specified.

" thereoif on line-2+2 of Fig. 1.

Patented Aug. 11, 1931 UNITED s'r rEs PATENTTOFFICEIT Fl l1 I a pugmu L. ms, or BUII'ALO, NEW YORK, ASSIGNOB TO Burrsno 'PBESSED STEEL 00., g

g g I ornnn'ALo, nswvxonx g a t I I mm i} Application flcdseptcmber is as; semi no. aaaaai.

This invention relates to silencers or mufflers' ffor reducing the noise caused by dis olitrge ofgas suchyfor:example, asnn the g V eithaust 05 an internal combustion engine. l The objects of thisinvention are to provides. niufller of this kind of compact construetien in whichfthe gases in flowing mugh the mufiler aresuccessively subjected to afi action the reverse of that of a megaphone, for the purpose of silencing the noise; to provide a mufller ofthis kindwith a plutality oftubes, one or more of which is sEei-ed'and which are arranged within each 6 to" roduce'a series of chambers, the erosssec onal areas'of which decrease in the direction of flow of the ases; also to provide a mufiler of this'kind -w ich is of simple and inexpensive construction, and whichis well adapted for production in large quantities;

' m also to produce a mumer of this. kind which is of aimple and inexpensive construction, and can easily be manufactured in large entities; also to improve the construction ofniuflers of this kind in other respectshere lathe accompanying drawings:- I FigJ is acentral sectional elevation of a mfl'er embodying this invention. c2 ."2 is a transverse, sectional elevation the a" fragmentary, lon 'tudinul, sectiona view of a mufier of slig tly modified eenstruction.- Y

l'he mufller which is shown in the accompanying drawings, and which illustrates by way of example, one embodiment of my in- ;Tention, includes an outer tube or shell A which may be cylindrical in form,'and B represents an intermediate shell, both of the '10 A and B being of substantially the flength and being connected at their heads'C and D in any usualor suitahiamanner. The intermediate shell B may cylindrical or of tapered form, latter 02m being preferred. In the construction shown, this shell is of largest diameter adjieent to the head 1) at the discharge end of themufller, and which head is provided with a tubular discharge part d. g j.- 1: represents the inner shell of the mufller .gasmirom the engine enter into the larger which is. of tapered? form, having its lar r end at the receivingend of the mufilen, Y

head C is provided with a short tubular inlet portion 0. to whichthet, exhaust pipe of the engine is connected and through which the end of the inner shell E. The head C is provided with the usual'shoulder5 to which the adjacent ends of the inner and intermediate shells are secured in any suitable manner, for example, by welding. The 'opposite end of the innershell in the, construction'shown in Figs. v1 and 2 issecured to a baflie F which has a projecting boss 'orTpart 6 to which the smaller end of t e inner tube is secured. This baflle also has an outer. flange 7 to which may be :welded or otherwise secured the inner wall of the intermediate shell B. Thcinner'sh'ell Eis provided near the discharge end thereof with a plurality of orifices or dischar'geopenings 10 through which or productsof combustion may pass s intoa chamber 11 between the intermediate and inner shells. Theintermediate shell. is provided adjacent to the receiving end of the muflier with correspondin orificesor holes'm from which gases from t e chamber 11 may discharge into a chamber 13 formed between the intermediate and outer shells. The intermediate shellis'al's'o provided beyond, the 'baflle F with aseries of discharge openings 14 through which'the ases enter'fromthe chamber'13into the discharge chamber 15 of theintermediate. shell which is separated from the chamber 11 and from the, interior of 5*; the inner shell by the baflie. F. The gases after passin into the discharge chamber of the interme iate shellare discharged from the muflier through the tubular projection d of the head D. H desired, a series of-aperture's 16 ma be provided in the bafile F so that gases 7 om the chamber 11 may dis- 1 charge directlyv into the discharge chamber ofthe intermediate shell. T

-l In the modified construction shown inEig. 05 3, the inner shell E and the baflle F are of slightly different construction, the bafilo being spaced from the end of the inner shell which is supported entirely by the welded connection tothe head Czattherecempgce of the mufiler shown in Fig. 1. In this case, the gases discharged into the inner shell pass not only through the holes or perforations in the shell, but also through the open end of this inner shell into the chamber between the inner and intermediate shells. In other respects, the muffler may be similar to the one shown in Figs. 1 and 2.

The structures described result in the following operation and advantages:

By making the inner shell of tapered or frusto-conical form and discharging the gases into the larger end thereof, an unexpected silencing action is produced which may be due to an action the reverse of that obtained in a megaphone. By arranging a tapered inner shell within the intermediate shell, the gases after passing through the discharge openings 10 in the inner shell, or through the open end of the inner shell shown in Fig. 8, enter into the portion of the chamber 11 of greatest cross section area, and flow in the direction indicated by the arrows toward the end of the chamber of lesser cross sectional area. This again results in a silencing action, the reverse of that of a megaphone. If the intermediate shell is also tapered, as shown in the drawings, the same action is obtained for the third time when the gases pass into the outer chamber 13 through the holes 12, since the gases then again pass from portions of the-chamber 13 of greater cross sectional area to portions of lesser cross sectional area. Upon their final discharge into the discharge chamber in the intermediate shell through the apertures 1% thereof, these gases will flow radially toward each other in such a manner that the various jets or curreirs of gases will impinge upon each other, resulting in a further rethiction of noise.

Preferably, although not necessarily, by providing a comparatively small number of apertures 16 in the baffle F, some of the gases in the chamber 11. will discharge through these apertures directly into the discharge chamber of the inner shell, and by flowing in a direction at an angle to the gases entering through the openings 1%, a further silencing etlect is produced and the back pressure of the mutller is also considerably reduced thereby.

Heretofore, it has generally been assumed that the best mullling or silencing action is obtained if the gases are discharged from one chamber to another in such a manner as to be continually expanded. I found. however, that such arrangement of the mullling chambers not necessary, and in the construction illustrated, the silencing of the is effected by causing them to flow from the portion of a chamber of larger cross sectional area to a portion of smaller area. with a very ellicient reduction in the noise and low back pressure, an action the reverse of that of a megaphone being probably responsible for this silencing efi'ect.

The construction described also lends itself exceptionally well to quantity production, since by a preliminary operation, the inner shell E may be secured to the baflle F by welding or other suitable means. This assembly is then easily inserted from the larger end of the intermediate shell and is guided into its final position by the taper of the intermediate shell, and the outer flange 7 of the battle F is then spot welded or otherwise secured to the intermediate shell B. The heads C and D and the outer shell A may then readily be assembled to the intermediate shell assembly. By this arrangement, all of the parts that require welding are readily accessible for welding and inspection at various stages during the assembling of the mulller.

Claims 1. A muffler including a tapered shell arranged to receive gases at the larger end thereof and having an opening near the other end thereof to discharge gases, a second tapering shell surrounding said first mentioned. shell and having its taper extending in the opposite direction and having discharge openings near the end thereof of smaller diameter, whereby the gases successively pass from one shell into another and from a portion of greater cross sectional area to a portion of lesser cross sectional area in each shell.

2. A mulllcr including a tapered inner shell, a tapered intermediate shell within which said inner shell is arranged, the tapers of the two shells extending in opposite directions, and an outer shell surrounding said intermediate shell, said shells forming between them chambers with relatively converging walls. said inner and intermediate shells having discharge apertures to permit gases to pass from one chamber to another and to enter each chamber at a portion of greater cross sectional area and to leave the chamber at a portion of lesser cross sectional area.

3. 1 muttler including an inner tapered shell and an intermediate shell within which said inner shell is arranged and which is tapered in the opposite direction, a. transverse bafile arranged within said intermediate shell, said inner shell terminating adjacent one side of said ballle, and an outer shell arranged about said intermediate shell, said inner and intermediate shells being provided with apertures for discharging the gases successively into several chambers formed by said shells and battle, the gases entering into the larger end of the inner shell and being discharged near the opposite end thereof one side of said barlle. and being in turn. discharged through apertures at the larger end of said intermediate shell into the chamber between said intermediate and outer shell and then into said intermediate shell at the opposite side of said baflle.

4. A mufller including outer and intermediate shells, heads to which said shells are secured for spacing said shells apart to form a chamber between said shells, a baflle in said intermediate shell dividing said intermediate shell into two chambers, an inner tapered shell in said intermediate shell at one side of said baflle and arranged to receive s at the larger end thereof and to form a c amber with relatively converging walls with a part of said intermediate shell, said inner shell having means for discharging gases into the end of greater cross sectional area of said lastmentioned chamber, said intermediate shell havin openings for discharging gases to the chem er between said intermediate and outer shells and thence into the chamber in said intermediate shell at the other side of said baflle, and means for discharging gases from said last mentioned chamber.

5. A mufller including outer and intermediate shells, heads to which said shells are secured for spacing said shells apart to form a chamber between said shells, a bafile in said intermediate shell dividing said intermediate shell into two chambers, an inner tapered shell in said intermediate shell at one side of said baflle and arranged toreceive gases at the larger end thereof and to form a chamber with relatively converging walls with a part of said intermediate she I, said inner shell having means for discharging gases into the last mentioned chamber, and an aperture in said baflle for discharging some gases directly from one chamber of "said intermediate shell 36318 other chamber of said intermediate 6. A mufler including an inlet end and a said intermediate shell adjacent to the discharge end of the mufller;

7. A mufiler including an inlet end and a discharge end, and havmg outer and intermediate shells, heads to which said shells are secured for spacing said shells apart to form a chamber between said shells, said intermediate shell being tapered and having its larger end at the discharge'end of the mufller, a baflle dividing said intermediate shell into two chambers, a tapering inner shell in said intermediate shell at the side of said baflle adjacent to the inlet end of the mufller and arranged to receive gases at the larger end thereof, said inner and intermediate shells having apertures therein positioned for successively discharging gases through the several chambers of the mufiler and finally to the chamber of saidintermediate shell adjacent to the discharge end of the mufller, and a restricted passage for gases in said bafile for passing some gases directly from the chamber at the inlet end of said intermediate shell to the chamber at the discharge'end of said intermediate shell. I I

8. A muflier having substantially concentrio tapering shells arranged one within the A other with their tapers extending in opposite directions, means for admitting gases into said shells at the portions thereof of larger cross sectional areas and discharging gases at portions thereof of lesser cross sectional areas,

and an outer shell surrounding said shells and forming with the larger of said first mentioned shells a chamber with relatively converging walls, means for discharging gases into a portion of said chamber of greater cross sectional area, and means for discharging the gases from a portion of said chamber of lesser cross sectional area.

LUCIEN L. HAAS.

discharge end, andehaving outer and intermediate shells, heads to which said shells are secured for spacing said shells apart to form a chamber between'said shells, said intermediate shell being tapered and having its larger end at the discharge end of the mufler,

abame dividing said intermediate shell into two chambers, a tapering inner shell in said in ermediate shell at the side of said baflfle adjacent to the inlet end of the mufiler and arranged to receive gases at the larger end thereof, said inner and intermediate shells having apertures therein positioned for suceessively discharging gases through the several chambers of the mufler and to cause the gases to pass from the'portion of greater to the portion of lesser cross sectional area of each chamber and'finally to the chamber of 

